DESC:Field of the invention
The present invention relates to a mounting assembly. In particular, the invention relates to magnetic mounting of Fiber optical sensor on the rail. The area of concern of this system is mounting of Fiber optical sensor on the rail using magnetic support for monitoring the railway vehicle.
Background
Fiber Bragg grating (FBG) sensors have attracted a considerable amount of interest in optical fiber sensing applications. FBG sensors are made on a bare fiber using Ultra Violet (UV) radiations. This sensor is very sensitive and leads to shift in Bragg wavelength of the sensor due to variation in strain, temperature, pressure etc.
FBG sensors are packaged and mounted on rail using adhesive material, spot welding etc to measure strain of relatively large or heavy structures. This technique is useful for fixed sensors. The main disadvantage of this type of mounting is lack of interchangeability. The mounting using glue or welding provides effective results but damage the sensor while deploying. In this case, a new sensor must be fitted, which is disadvantageous because the sensor fibers which are expensive to manufacture have high initial costs. Adhesive joints are also unfavorable in those cases in which an object is to be measured only once.
Various methods are known for mounting of FBG sensors on rail, but have their own limitations. In any case, such fixtures are complicated, time consuming and costly and there is a need to design a mounting assembly with magnets that can attach/detach from the rail structure easily and quickly without damage. Such mounting assembly provides greater security with quick mounting solution.
Thus, there is enormous scope of simple, scalable, efficient, reliable and cost effective apparatuses which allow for quick and easy attachment and release of the sensors.
The Application No. DE102011083028A1, entitled “Mounting Assembly for mounting strain measuring element such as Fiber Bragg grating (FBG) sensor on measurement object, has two holding units through which the strain measuring elements are releasably fixed in the assembled state” relates to a mounting assembly comprises a holder for fixing the strain measuring element, and a fixing unit for fixing the mounting assembly on the measurement object. The holding comprises at least two brackets, in which FBG or other sensor is releasably fixed using screw, rivets or bolts in the assembled state.
But this mounting assembly includes two holders and fixing unit (screw, bolts etc.) for fixing sensor on the rail structure is complicated and time consuming.
The Application No. CN102076527B, entitled “Device for the support of Portable electronic equipment provided with a magnetic support” relates to connecting device of portable electronic equipment particularly automobile driver and the passenger carriage of finned vent window. The invention comprises the magnetic base having an attraction seat to house the coupling interface of the coupling plate, consist of the coplanar approaching of at least two permanent magnets reciprocally attracted with one another. But the device described is having complex mechanical structure and useful in car driver and passenger compartment having ventilation air vents.
The Article, IEEE Sensors Journal, July 2005 National Taiwan University, entitled “Packaging Methods of Fiber Bragg Grating sensors in civil structure applications” relates to different methods of packaging of FBG sensors to protect the sensors. The method includes Nickel recoating, quartz glue, steel tubing with 2-mm wall thickness. Finite –Element Analysis (FEM) with plane stress element simulation is employed to evaluate the adhesive interface effects. But, the document is evaluating the strain transmission to get good packaged FBG sensor and then surface mounting for measuring strain of structure.
Therefore, a mounting assembly for time efficient monitoring of strain, portable structure, reusable and less man power requirement is highly desired.
Summary of invention
The present invention fulfils the foregoing needs by providing a mounting assembly and method of magnetic mounting of FBG sensors on the rail. The assembly includes a base surface and two magnets. FBG sensors are attached along the axis of base. The magnets fix the base which is having sensor followed by optical fiber cable, with the rail due to its strong magnetic property. These magnets are attached at another side of the base surface where the sensor is fixed.
Also, the assembly for mounting FBG sensor on the rail uses strong neodymium magnets which are rare earth magnets. The magnets presents at another side of base surface are get attached with the rail.
Further, the method of mounting of FBG sensors using magnets includes pasting of sensors on the base surface along its axis using adhesives; followed by fixing of said base surface having sensor and optical fiber cable on the rail, using two or more magnets. The magnets are attached to another side of base surface having FBG sensor, and also perpendicular to the axis of base surface.
When the train passes over the rail, FBG mounted with novel assembly calculates strain by change in wavelength of optical sensors. Hence a modular assembly with magnetic mounting is leveraged to deploy portable FBG sensor on rail. The portability and magnets saves the sensors from damage and can be reused.
Brief description of figures
Exemplary embodiments of the present invention will become more fully understood from the description and the accompanying figures, wherein:
Figure 1: Illustrate assembly structure section view.
Figure 2(a,b): shows mounting of assembly on the rail.
Figure 3(a,b,c): shows the train data showing axles.
Detailed description of invention
The foregoing description of the embodiments, the various features, and advantageous details of the invention has been presented for the purpose of illustration. It is not intended to be exhaustive or to limit the invention to the precise form disclosed as many modifications and variations are possible in light of this disclosure for a person skilled in the art in view of the figures and description. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by person skilled in the art.
The embodiments herein below provide mounting assembly and method of mounting of sensors to deploy portable FBG on the rail for strain or other calculations.
Fig 1 illustrate Assembly structure 100 comprises base 10, magnets (20, 30), fiber optical cable 50 with grating. The assembly having base 10 on which FBG sensor 40 is fixed using adhesive along the axial direction of the base 10. Two strong magnets (20, 30) are attached opposite to axial direction of the base to fix optical fiber cable 50 with the base 10.
Further, the base 10 is Aluminum foil, card board or plastic etc.
Further, pair of strong magnets (20, 30) is Neodymium Magnets which is rare earth magnets.
Fig.2a shows the mounting of FBG assembly structure on the rail 130 to monitor the railway vehicle. The assembly structure 100 is mounted on web 120 using magnets. The permanent magnets fix the assembly structure 100 with the rail 130.
Fig.2b shows image of FBG Mounting on the rail.
Further, the mounting of assembly structure is on the web of rail, foot of rail, or down the flat bottom of rail etc.
Fig.3a shows the raw data of a train showing Train axles. Fig. 3b is an intermediate data after processing. Fig.3c is digital data after filtration showing clearly all the train axles.
Hence, the proposed system provides real time monitoring of railway vehicle using assembly structure. The proposed assembly structure provides portable FBG sensor that can be attach/detach from the rail structure easily and quickly without damage.

,CLAIMS:We Claim:
1. Assembly 100 for mounting a fiber optical sensors 40 on the rail 130, comprising:
a base surface 10 for fixing the sensor 40 along the axial direction;
at least two metal pieces for fixing the base surface 10 having at least one sensor 40 and an optical fiber cable 50 with the rail 130 wherein said metal pieces are attached along the rail 130, at opposite side of the base surface 10, where the sensor 40 is pasted.
2. An Assembly 100 as claimed in claim 1, wherein the base surface 10 is at least one of the materials includes aluminum sheet, plastic sheet, card board etc.
3. An Assembly 100 as claimed in claim 1, wherein the metal pieces are strong magnets (20, 30).
4. An Assembly 100 as claimed in claim 3, wherein the magnets (20, 30) are Neodymium magnets.
5. An Assembly 100 as claimed in claim 1, wherein the sensor 40 is fixed on the web 120 of the rail 130 using magnets (20, 30).
6. An Assembly 100 as claimed in claim 1, wherein fixing of sensor 40 on base surface 10 using at least one of adhesive material includes glue, steel tape etc.
7. An Assembly 100 as claimed in claim 6, wherein the sensors 40 are Fiber Bragg Grating sensors.
8. A method for mounting fiber optical sensor 40 on a rail 130, comprising:
pasting of sensors 40 on the base surface 10 along axial direction using adhesives;
fixing of the base surface 10 having sensor 40 and an optical fiber cable 50 on the rail 130, using two or more magnets (20, 30) wherein the magnets (20, 30) are attached to opposite side of base surface 10 having fixed sensor 40, and also perpendicular to the axis of base surface 10.
9. A system for real time monitoring of railway vehicle, comprising:
An assembly structure 100 having sensor 40 inserted on web 120 of rail 130 using base surface 10 and magnets (20, 30) to obtain strain in form of wavelength shift;
an optoelectronic instrument to analyze change in Bragg wavelength due to strain;
a data processing unit (DPU) to process change in Bragg wavelength and generate data continuously;
GUI of authorized person displays the axles of railway vehicle corresponds to amplitude w.r.t time.